Surgical treatment

ABSTRACT

The invention concerns a surgical instrument whose distal end region is to be introduced or inserted by a puncture into a cavity of a patient&#39;s body. The surgical instrument has an outer trocar sleeve (1) and a trocar mandrel (2) which can be inserted in the latter and is guided in a sliding manner. When slid into an end position, the distal tip (4) of the trocar mandrel (4) projects beyond the end region (3) of the trocar sleeve (1), which end region is inclined relative to the longitudinal axis of the sleeve. In order to keep the distance between the trocar mandrel tip (4) and the distal end (6) of the trocar sleeve (1) as small as possible and to reduce the risk of injury to the patient when the surgical instrument is inserted by a puncture, it is proposed according to the invention that the trocar mandrel tip (4) is eccentric relative to the longitudinal axis of the trocar mandrel and is disposed in the region of the distal end (6) of the trocar sleeve (1) facing the patient.

BACKGROUND OF THE INVENTION

The invention concerns a surgical instrument whose distal end region isto be introduced or inserted by a puncture into a cavity of a patient'sbody, the surgical instrument having an outer trocar sleeve and a trocarmandrel which can be inserted in the latter and is guided in a slidingmanner, whereby, when slid into an end position, the distal tip of thetrocar mandrel projects beyond the end region of the trocar sleeve,which end region is inclined relative to the longitudinal axis of thesleeve.

Surgical instruments of the type mentioned at the outset are used inminimum invasive surgery for diagnosis and surgery on the living body ofa patient.

Thus to perform an intraabdominal operation, first an insufflationneedle is passed through the patient's abdominal cavity. This hollowinsufflation needle is connected by tubing to a gas source to enable thepatient's abdominal cavity to be filled with gas and suitably dilated.After the abdominal cavity has been dilated, the surgical instrument isinserted by a puncture, practically blindly, into the body cavity, thetrocar mandrel being inserted in the trocar sleeve and the trocarmandrel tip projecting beyond the distal end of the sleeve.

After the surgical instrument has been inserted by a puncture, thetrocar mandrel can be removed from the trocar sleeve and replaced byoptical observing instruments, grippers, thread holders, forceps orsimilar surgical instruments.

The trocar mandrel is usually cone-shaped at its trocar mandrel tip, soas to facilitate piercing through the layers of tissue. Trocar mandrelswith polygonal trocar mandrel tips have also already been provided,these acting like a knife and practically opening the intractableperitoneum. However these usually three-edged trocar mandrel tips havethe drawback of producing severe and large lacerations in the event ofinadvertent injury.

To facilitate pushing the trocar sleeve further after the peritoneum hasbeen pierced with the aid of the trocar mandrel, it is already knownthat the distal end of the trocar sleeve be arranged slantwise relativeto the longitudinal axis of the sleeve. For the slanted sleeve openingof the trocar sleeve meets with less resistance by tissue, so that thetrocar sleeve can slide better.

The so-called "tent" phenomenon during insertion of the trocar mandrelby a puncture is known, according to which the intractable peritoneumrecedes inwardly to the pointed trocar mandrel and deflects in a"tent-like" fashion before the puncture wanted is established. In sodoing, the trocar mandrel tip is liable to enter the vicinity of theabdominal organs, substantially increasing the risk of considerableinjury to the patient.

Excessive penetration of the trocar mandrel inserted in the trocarsleeve into a cavity of the body can lead to mortal injuries to internalorgans or blood vessels by the trocar mandrel tip.

A surgical instrument having a piercing means insertable in a trocar isalready known from U.S. Pat. No. 5,224,951. This piercing means has anouter cutting sleeve in which a protective rod is guided in a slidingmanner. The distal end of the outer cutting sleeve is disposed inclinedrelative to the longitudinal axis of the sleeve in such a way that thedistal end edge of the sleeve tapers to a two-bladed puncturing tipsituated to the fore as considered in the direction of puncture. As soonas the piercing means of the known surgical instrument meets the bodytissue, the protective rod can move slightly into the interior of thesleeve so that the puncturing tip is cleared. The protective rod, whichin practice is formed as a blunt plastic part, has at its distal end twoslanted flanks which are to prevent the tissue from being cored by thekeen edge of the outer cutting sleeve, as well to prevent cored piecesof tissue from entering the interior of the sleeve.

Since in the known surgical instrument according to U.S. Pat. No.5,224,951 the cutting sleeve tapers slantwise at its distal end to apuncturing tip and is provided for a trocar whose distal end is disposedat right angles to the longitudinal axis of the trocar, here as well thedistal end of the cutting sleeve has to be advanced outwards a long waybeyond the adjacent end of the trocar. The risk of injury, which isanyway already high because of the two-bladed puncturing tip, istherefore further increased.

In WO-A-93/17626 a surgical instrument is described in which the trocarmandrel guided in a sliding manner in a trocar sleeve co-operates with aretracting device disposed at the proximal end of the trocar sleeve. Theretracting device holds the trocar mandrel in its advanced operativeposition as the tissue is pierced and retracts it into the trocar sleeveas soon as the trocar mandrel is relieved. However, to assume itspiercing position the trocar mandrel tip, which in some embodiments ofWO-A-93/17626 is also eccentric relative to the longitudinal axis of thetrocar mandrel, has to be advanced a long way beyond the distal end ofthe trocar sleeve disposed at right angles to the longitudinal axis ofthe sleeve. This again produces an unnecessarily long sliding path and acorrespondingly high risk of injury as the trocar mandrel is inserted bya puncture and as the trocar sleeve is pushed further.

A surgical instrument is already known from U.S. Pat. No. 5,256,147 inwhich a plurality of replaceable trocar mandrel tips are associated withthe trocar mandrel that is guided in a sliding manner in a trocarsleeve. The trocar mandrel of the known surgical instrument has for thispurpose a trocar mandrel shank on which one trocar mandrel tip at a timecan be fixed in a detachable fashion. In the use position inserted inthe trocar sleeve, this trocar mandrel tip is securely retained on thetrocar mandrel shank and partially projects beyond the trocar sleeve endoriented at right angles to the longitudinal axis of the sleeve. Theknown surgical instrument according to U.S. Pat. No. 5,256,147 has,inter alia, trocar mandrel tips with slanted tip ends. However, thesetrocar mandrel tips also have to be advanced a long way beyond the endopening of the trocar sleeve, this entailing the risks mentioned for thepatient.

A surgical instrument with a trocar sleeve is already described in EP 0604 197 A2, in which the distal sleeve opening facing the patient isoccluded by means of a safety shield. This safety shield is composed ofa plurality of generally conically disposed parts which, as a trocarmandrel is advanced, spring outwards and clear the sleeve openingbetween them. Here, too, the trocar mandrel has to be advanced furtherbeyond the sleeve opening to assume its puncturing position, in orderthat its trocar mandrel tip also projects beyond the lateral parts ofthe safety shield.

A surgical instrument constituting a combination of an outer trocarsleeve and, slidably guided in the latter, an inner needle or cannula,is already known from WO-A-93/10837. While the trocar sleeve here alsohas a sleeve opening oriented at right angles to the longitudinal axisof the sleeve, the needle or cannular has a distal end disposed at aninclination to its longitudinal axis. To reduce the risk of injuryinvolved by the needle tip projecting a long way beyond the opening ofthe trocar sleeve, it is proposed in WO-A-93/10837 that, upon pressurerelief, the needle or cannula is automatically retracted into theinterior of the trocar sleeve. However, by this means the needle tipprojecting a long way beyond the trocar sleeve cannot be prevented fromleading to inadvertent injury until such time as it is situated insidethe sleeve.

SUMMARY OF THE INVENTION

The object underlying the invention is therefore particularly to providea surgical instrument of the type mentioned at the outside, whose useinvolves a substantially smaller risk of injury to the patient.

This object is accomplished according to the invention in the surgicalinstrument of the kind mentioned at the outset particularly in that thetrocar mandrel tip is eccentric relative to the longitudinal axis of thetrocar mandrel and is disposed in the region of the distal end of thetrocar sleeve facing the patient.

The eccentric arrangement of the trocar mandrel tip permits the distancebetween the distal tip of the trocar mandrel and the respective end ofthe trocar sleeve to be kept comparatively small. By virtue of theeccentric arrangement of the trocar mandrel tip, the sliding pathnecessary as the trocar mandrel is inserted by a puncture and as thetrocar sleeve is pushed further is considerably reduced. As a smallersliding path is necessary for piercing, for instance, the patient'sabdominal wall (of the peritoneum) with the aid of the surgicalinstrument according to the invention, the risk of inadvertent injury tothe patient's internal organs and blood vessels is also reduced.

In order that as it pierces, the trocar mandrel tip meets with as littleresistance as possible by the tissue, a preferred embodiment of theinvention proposes that the distal end region of the trocar mandrelessentially takes the form of an intersection or a curve of intersectionbetween a cylinder oriented approximately in the longitudinal directionof the sleeve and a cone. The end surface facing the patient of thetrocar mandrel according to the invention is therefore also essentiallyadapted to a part of the surface of a cone.

In performing known operation methods in which, after having dilated theabdominal cavity, the surgical instrument comprising trocar sleeve andtrocar mandrel is pierced, practically blindly, through the patient'slayers of tissue, it is suitable if the cone tip of the trocar mandreladapted to part of the surface of a cone is disposed outside the crosssection of the trocar or approximately on the circumference of thetrocar mandrel. Particularly if the trocar mandrel tip is arrangedapproximately on the circumference of the trocar mandrel, this trocarmandrel tip, here also tapering to a point, projects only slightlybeyond the distal end of the trocar sleeve.

An advantageous further development according to the invention proposesthat the trocar tip is disposed within the cross section of the trocarmandrel and is preferably spaced from the longitudinal axis of thetrocar mandrel on the one hand and from the circumference of the trocarmandrel on the other. Such a trocar mandrel tip offset relative to thelongitudinal axis of the trocar mandrel as well as relative to thecircumference of trocar mandrel permits the configuration of acomparatively flat plane of the tip which can be of advantageparticularly for smaller trocars.

The trocar mandrel tip of the surgical instrument according to theinvention can taper to a point. It is also possible, however, that thetrocar mandrel tip is of knife-shaped configuration or is slightlyrounded off at the end. Particularly with a trocar mandrel tip slightlyrounded off at the end, the risk of injury can be reduced even further.

A preferred embodiment of the invention proposes that the trocar mandreland/or the trocar sleeve is/are provided with at least one anti-rotationmeans which is operative at least in an end position of slide and servesto safeguard the relative position of trocar sleeve and trocar mandrelin their circumferential direction. In this embodiment, the rotaryposition or relative position between trocar sleeve and trocar mandrelis safeguarded in the end position of slide in which the eccentrictrocar mandrel tip is disposed in the region of the distal end of thetrocar sleeve facing the patient. It may be advantageous in this regardif these anti-rotation means are lockable so that the two instrumentparts do not have to be held in their end position of slide by theoperating surgeon.

It is suitable if provided at the proximal end region of the trocarmandrel or trocar sleeve is at least one anti-rotation projection which,at least in an end position of slide, engages with an anti-rotationrecess of the other instrument part. For instance, this anti-rotationprojection can be provided at the proximal end region forming a handleof the trocar mandrel, in an end position of slide this anti-rotationprojection engaging with an anti-rotation recess provided at theadjacent proximal end of the trocar sleeve.

The trocar mandrel of the surgical instrument according to the inventionpreferably has a trocar mandrel tip substantially adapted in shape to apart of the surface of a cone. The trocar mandrel can also have asurface tapering with a convexity or concavity to its trocar mandreltip.

Another embodiment and further development of the invention concerns asurgical instrument of the type mentioned at the outset in which atleast one gas duct terminating in the region of a gas inlet opening orgas outlet opening of the trocar sleeve is provided between the trocarmandrel and the trocar sleeve. With the aid of such a gas duct betweenthe trocar mandrel and the trocar sleeve, the escape of gas at the gasoutlet opening of the trocar sleeve permits that during the conventionalprocess of insertion one can determine when the surgical instrument haspierced the patient's peritoneum dilated by means of the insufflationneedle. In such a surgical instrument it is proposed according to theinvention that a signalling whistle is downstream of the gas outletopening of the trocar sleeve, as considered in the direction of outflow.With the aid of such a signalling whistle it can be determined with asubstantially greater degree of reliability whether the surgicalinstrument has penetrated the peritoneum and whether the gas previouslyintroduced into the abdominal cavity is escaping by way of the gasoutlet opening of the trocar sleeve. Since further advancement of thesurgical instrument into the abdominal cavity can be stopped or at leastslowed down when the signalling whistle sounds, inadvertent injury tothe patient is also avoided.

It is advantageous in this regard if the trocar mandrel has between itstwo end regions a portion of reduced cross section defining a gas ductbetween the trocar mandrel and the inside wall of the trocar sleeve, andif provided at the distal end region of the trocar mandrel is apreferably groove-like duct portion leading from the trocar mandrel tipto the reduced cross-sectional region of the trocar mandrel. This trocarmandrel formed with a reduced cross section in a comparatively largeportion of its longitudinal expanse can be cleaned particularly well.

The portion of reduced cross-section of the trocar mandrel can have byway of example a cross-shaped section or be composed only of three orfour connecting rods joining the front part - possibly solid in design -of the trocar mandrel to the proximal end region taking the form of ahandle of the trocar mandrel.

Further features of the invention follow from the following descriptionof exemplary embodiments of the invention, taken in conjunction with theclaims and the drawings. The individual features may be realized singlyor severally in an embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING

In the drawings

FIG. 1 is a perspective view of a trocar mandrel having a trocar mandreltip that is eccentric relative to the longitudinal axis of the trocarmandrel,

FIG. 2 is a perspective view of a trocar sleeve associated with thetrocar mandrel of FIG. 1, this trocar sleeve and the trocar mandrelcomposing a surgical instrument, and

FIG. 3 is a surgical instrument, similar to that of FIGS. 1 and 2, withthe trocar mandrel of this surgical instrument inserted in the trocarsleeve.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 2 depicts a trocar sleeve 1 in which a trocar mandrel 2, shown inFIG. 1, is guided in a sliding manner. Trocar sleeve 1 and trocarmandrel 2 compose a surgical instrument which is usable in minimuminvasive surgery and for that purpose can be inserted by a puncture intothe cavity of a patient's body.

For inserting the surgical instrument by a puncture, the trocar mandrel2, when inserted in the trocar sleeve 1 and slid into an end position,projects beyond the distal end region 3 of the trocar sleeve 1. At thesame time, the sleeve opening provided at the distal end region 3 of thetrocar sleeve 1 is slanted relative to the longitudinal axis of thetrocar sleeve so as to facilitate pushing the trocar sleeve 1 further asthe surgical instrument is inserted.

The trocar mandrel tip 4 of the trocar mandrel 2 is arrangedeccentrically relative to the longitudinal axis of the trocar mandrel.As becomes apparent from FIG. 1, the distal end region 5 of the trocarmandrel 2 is essentially formed as an intersection or a curve ofintersection between a cylinder oriented approximately in thelongitudinal direction of the sleeve and a cone. The cone tip of thiscone, which here simultaneously also composes the trocar mandrel tip 4,is arranged on the circumference of the trocar mandrel and tapers to apoint.

By means of the eccentric configuration of the trocar mandrel tip 4 andits arrangement in the region of the foremost end 6 of the trocar sleeve1 facing the patient, the trocar mandrel tip 4 indicated by dashed linesin FIG. 2 nevertheless projects only slightly beyond the distal openingof the trocar sleeve 1. The distance between the foremost end 6 of thetrocar sleeve 1 and the adjacent trocar mandrel tip 4 is therebysubstantially reduced and the surgical instrument has to be advancedless far through the abdominal wall until the trocar sleeve haspenetrated the by nature intractable peritoneum receding in a"tent-like" fashion.

Provided at the proximal end region taking the form of a handle 7 of thetrocar mandrel 2 is an anti-rotation projection 8 which, in the endposition of slide, engages with a corresponding anti-rotation recess(not shown) provided at the adjacent proximal end of the trocar sleeve1.

As becomes apparent from FIG. 1, the distal front part 9 of the trocarmandrel is a solid element and has a substantially cylindrical outercircumference corresponding to the inside diameter of the trocarsleeve 1. In the portion arranged between the handle 7 of the trocarmandrel 2 and the tip 4 or front part 9 of the trocar mandrel, thetrocar mandrel 2 has a reduced cross section defining a gas duct betweenthe trocar mandrel and the inside wall of the trocar sleeve. When thetrocar mandrel is slid into the end position, the gas duct terminates ina gas inlet and outlet opening 10 of the trocar sleeve 1.

In this reduced cross-sectional region of the trocar mandrel 2 there areonly four connecting rods 11 joining the handle 7 of the trocar mandrelto the front part 9 of the trocar mandrel. Of these four connecting rods11, only two rods 11 are to be seen in FIG. 1.

Provided at the distal end region 5 of the trocar mandrel 2 is agroove-like duct portion 12 leading from the trocar mandrel tip 4 to thereduced cross-sectional region of the trocar mandrel 2.

Once the surgical instrument has been inserted by a puncture and thefront part 9 of the trocar mandrel has in a known manner penetrated theperitoneum of the abdominal cavity dilated by gas insufflation, this isindicated to the operating surgeon when the gas fizzes from there,escaping by way of the duct portion 12, by way of the gas duct kept freeby the connecting rods 11 and by way the gas outlet opening 10 of thetrocar sleeve 1.

It may be suitable in this connection if a signalling whistle isdownstream of the gas outlet opening 10 of the trocar sleeve 1, asconsidered in the direction of outflow. When the signalling whistlesounds, the operating surgeon can slow down or stop the process ofinsertion by a puncture before he inadvertently injures the patient'sinternal organs or vessels.

FIG. 3 shows a surgical instrument whose trocar mandrel tip 4 islikewise eccentric relative to the longitudinal axis of the trocarmandrel and is adapted to part of the surface of a cone. The trocarmandrel tip 4 is provided within the cross section of the trocar mandreland is spaced from the longitudinal axis of the trocar mandrel on theone hand, and from the circumference of the trocar mandrel on the other.This arrangement of the trocar mandrel tip 4, as depicted in FIG. 2,permits a flatter plane of the tip to be provided, particularly fortrocar sleeves of smaller diameter.

As FIG. 3 shows, the trocar mandrel tip 4 is slightly rounded off here,so as to additionally reduce the risk of injury by the surgicalinstrument depicted in FIG. 3.

To sum up it can be said that, by virtue of the eccentric configurationof the trocar mandrel tip 4 relative to the longitudinal axis of thetrocar mandrel and by virtue of disposing this trocar mandrel tip 4 atthe distal end of the trocar sleeve 1 facing the patient, the risk ofinjury to the patient when the surgical instrument is inserted by apuncture is substantially reduced.

I claim:
 1. A surgical instrument having a distal end region adapted forintroduction into a body cavity by a puncture, comprising:an outertrocar sleeve (1) having a longitudinal axis, an end region (3), asleeve distal end (6) and a proximal end; and a trocar mandrel (2)having a longitudinal axis, a cross section, a mandrel distal end region(5), a distal tip (4), and a mandrel proximal end; wherein said trocarmandrel (2) is insertable into said outer trocar sleeve (1) such thatsaid mandrel distal end region (5) of said trocar mandrel (2) isdisposed within said end region (3) of said outer trocar sleeve (1) andsaid distal tip (4) is offset from the central longitudinal axis of saidtrocar mandrel (2).
 2. The surgical instrument according to claim 1,wherein said mandrel distal end region (5) is formed as an intersectionbetween a cylinder oriented approximately in a direction of thelongitudinal axis and a cone.
 3. The surgical instrument according toclaim 1, wherein said distal tip (4) projects beyond said end region (3)of said outer trocar sleeve (1), and said sleeve distal end (6) isinclined relative to the longitudinal axis of said sleeve (1).
 4. Thesurgical instrument according to claim 1, wherein said distal tip (4) isdisplaced inwardly from a circumference of said trocar mandrel (2). 5.The surgical instrument according to claim 1, wherein said distal tip(4) is displaced one of outside of said cross section of said trocarmandrel (2) and on a circumference of the trocar mandrel (2).
 6. Thesurgical instrument according to claim 1, wherein said distal tip (4)has a knife-shaped configuration.
 7. The surgical instrument accordingto claim 1, wherein said distal tip (4) has a cone-shaped configuration.8. The surgical instrument according to claim 1, wherein said distal tip(4) is slightly rounded at the end.
 9. The surgical instrument accordingto claim 1, further comprising at least one anti-rotation means locatedon at least one of the trocar mandrel (2) and the trocar sleeve (1), theanti-rotation means being operative at least in an end position ofinsertion to prevent rotation of said trocar mandrel (2) relative tosaid outer trocar sleeve (1).
 10. The surgical instrument according toclaim 1, further comprising an anti-rotation projection (8) provided onsaid proximal end of said trocar mandrel (2) and an anti-rotation recessprovided on said proximal end of said trocar sleeve (1), wherein saidanti-rotation projection (8) is adapted for engagement with saidanti-rotation recess to prevent rotation of said trocar mandrel (2) insaid outer trocar sleeve (1).
 11. The surgical instrument according toclaim 1, wherein said trocar mandrel (2) has a surface which tapersrelative to said distal tip (4).
 12. The surgical instrument accordingto claim 11, wherein said tapering is convex relative to said distal tip(4).
 13. The surgical instrument according to claim 11, wherein saidtapering is concave relative to said distal tip (4).
 14. The surgicalinstrument according to claim 1, further comprising at least one gasduct provided between said trocar mandrel (2) and said trocar sleeve(1), a gas opening (10) provided on said trocar sleeve (1) and asignaling whistle, wherein said gas duct terminates at said gas opening(10) and said signaling whistle is downstream of said gas opening. 15.The surgical instrument according to claim 1, further comprising a gasduct located between said trocar mandrel (2) and the inside wall of saidtrocar sleeve (1), said gas duct being defined by a portion of reducedcross section of said trocar mandrel (2) between the proximal end andsaid distal end region (3) of said trocar mandrel (2), wherein saiddistal tip (4) further comprises a groove-like duct portion (12) leadingfrom said distal tip (4) to said reduced cross section of said trocarmandrel (2).